1. Field of the Invention
This invention relates to methods and apparatuses for automatically canceling turn signals (e.g., blinkers, indicator lights, etc.) of vehicles, in particular, motorcycles.
2. Description of the Related Art
Conventionally, four-wheeled vehicles such as automobiles have functions for automatically canceling turn signals when drivers return steering wheels to normal positions after steered with relatively large steering angles, which are greater than prescribed steering values. In contrast, two-wheeled vehicles such as motorcycles normally do not have functions for canceling turn signals (or indicator lights for indicating directions to turn) once operated by drivers. In addition, substantially no effective proposals are made with respect to the aforementioned functions because motorcycles may not allow provision of additional structures for automatically canceling turn signals.
Therefore, conventional motorcycles are designed to require manual operation for canceling turn signals by hands once operated. This may cause unexpected problems due to failure or negligence of canceling turn signals, which drivers may easily forget to perform. In other words, when drivers operate turn signals, which should be canceled thereafter, drivers may have difficulties in sustaining concentration in driving motorcycles.
Japanese Unexamined Patent Publication No. Sho 57-155131 discloses an example of an automatic blinker canceller using a geomagnetic sensor for a motorcycle and the like. According to this automatic blinker canceller, blinkers are automatically canceled under prescribed conditions where a difference of bearing detected between the turning direction and traveling direction becomes greater than a prescribed angle, and the motorcycle is restored in a straight drive mode just after turnabout.
However, the aforementioned automatic blinker canceller requires complicated processing in detection as to restoration of a straight drive mode, and it is therefore expensive.
It is an object of the invention to provide a method and an apparatus for automatically canceling turn signals of motorcycles without causing operation error, which can be manufactured at low cost.
An automatic turn signal canceller of this invention is constituted using a geomagnetic sensor for detection of axial components of the geomagnetism (or magnetic field) and a conversion table storing relationships between bearings, inclinations, and outputs of the geomagnetic sensor, which are measured in advance.
For example, the operator (or rider) of a motorcycle operates turn signals to indicate leftward or rightward turning of the traveling direction; then, the operator turns the traveling direction while inclining the motorcycle; thereafter, the operator restores the motorcycle to the normal position substantially perpendicular to the horizontal plane. In this case, when the bearing of the motorcycle is varied by a prescribed angle (e.g., 20xc2x0) or more after the operator operates the turn signals, and then, the inclination of the motorcycle is restored to the normal position substantially perpendicular to the horizontal plane, the turn signals are automatically canceled.
Thus, it is possible to reliably avoid occurrence of operation error in canceling turn signals due to operator""s failure or negligence. In addition, this invention can be easily realized at a relatively low cost because of the simple configuration thereof.